Man, reading this thread made me realize just how much I really miss playing this game.
I've always been intrigued by the mystery of TMA when I played 688i / SC / DW. I really didn't understand it back in the days of 688i H/K, but started to appreciate it more in the days of SC / DW.
That said, once the true bearing is confirmed, I could cook up a manual solution with a single sensor(TA), with a minimum of 5 lines, with accuracy of up to 3000 yards, which is more than enough tolerance for a bracket spread(with a ASW missile system) and just enough information to consider an intercept course for a close range attack run.
The downside is after I make contact, then lose contact, I have to reset my analysis all over again. If you choose to plot an intercept course, then this method won't matter anymore as you'll be in position for an attempt at M1.
When I played SC / DW, I used this method but with limitations. The limiting factors are detection ranges due to SSP type and what platform I'm driving. I'd prefer the Akula-II, Oscar-II, Virginia class, EDIT: Sturgeon or the fast attack 688i for RA mod 1.33. The ideal situation would be a target loitering around in a convergence zone at the 30nm null.
For submarines that have ASW missile capability, you have opportunity of attack with reduced risk. For submarines that do not have ASW missile capability, or those that do but elect not to use them, then you have opportunity with much higher risk as you are forced to close the distance between yourself and the target.
And if it's going to be a knife fight, I rather try for the target's baffles as to maximize the target's reaction time, giving me more time to escape possible danger.
As for triangulation of active sonar prosecution, I can determine the range of the target with just the initial ping of the prosecution(if I'm alert);

definitely by the 2nd consecutive ping.

If the target is staggering single pings over time, then there is the initial ping again,

but this time with estimated current range and course. But common sense would tell the target to clear bearing after use of active sonar, so as the aggressor, with estimated range and course data, my counteraction would be depending on what platform i'm driving.
Gosh I miss DW. I finally found a life which is why I don't play as much as I used to.
@ Molon:
Long time no see and I hope all is well, but if you are reading this, you now know why the Akula-II has always been, and will always be.. my true love..